Distributing system for telephone calls



NOV- 11, 1952 P. c. BoREL .E1-AL DISTRIBUTIG SYSTEM AFOR TELEPHONE CALLSFiled Apri1l4, 1948 y m62 mz3 INVENToRs amm.

ATTORNEY .llllllll Patented Nov. 11, 1952 DISTRIBUTING SYSTEM FORTELEPHONE CALLS Pierre Charles Borel, Boulogne, and Jean Raymond AntoineFont Escande and Marcel Roger Mauge, Paris, France, assignors toInternational Standard Electric Corporation, New

York, N. Y., a corporation of Delaware Application April 14, 1948,Serial No. 21,054 In France April 15, 1947 3 Claims.

The present invention relates to a system for distributing telephonecalls in automatic or semiautomatic:k telephone exchanges.

In automatic telephony systems in which calls are directed to theoperators position by means of line finders associated with the incominglines, it may happen that the line finders rotate continuously when allthe operators positions are busy.

In order to remedy this to some extent there have often been providedcircuits in which the incoming calls are registered and which enable.the line finders to resume rotation when one of the operators positionsis free. Such a device avoids unnecessary rotation of the line findersbut does not distribute the calls in the same order in which they werereceived and it may hap-pen that 'the last call received is given to thefirst free operator.

One object of the present invention resides in a distributing devicewhich will distribute calls in relation to their chronological incomingorder wi-thout keeping the line finders in rotation.

According to one feature of the present invention waiting positions areprovided on the line finders associated with each line on which thecalls accumulate in chronological order in the case of overload. When anoperator is free the line nder 4which has been engaged by the first callreceived starts rotating.

Other features and advantages of the present invention will be apparentfrom the following description of an embodiment in relation with thedrawing.

The iigure of the drawing. shows one of the line nders equipped withthree Waiting positions and any number of operators positions. It isclear that the number of waiting positions can be changed Withoutdeparting from the scope of the invention.

For the sake of clarity only the elements necessary to understand theinvention have been shown in the drawing. Each waiting positioncomprises three relays AZT, DZT, TZT. Indicia I, 2 or 3 denote relayscorresponding to the iirst, second or third waiting line. Theoverloading of the operators positions is indicated by the operation ofrelays TST and SUT.

Relay SUT is controlled by a chain of contacts provided in the operatorsposition circuits, which are closed when the corresponding operatorsposition is engaged.

When all the operators positions are busy, the chain of contactscontrolling relay SUT is closed and this relay operates. On the otherhand relay TST operates by a make contact of SUT through the restcontacts of AlTz and ALTi and applies a test potential to the terminalsof banks C of the finders. This test potential is given by a bat- .teryand a resistance in parallel with a winding of relay TIT. If a new calloccurs the corresponding finder begins to rotate and iindsy the testpotential'through a front contact ofA TSR. Relay TT operates and nder Ccomes to rest. Over ground of relay TR, relay TZT1 operates and locksindependently of contact TST and excites relay AZTi through back contactof DZT1. When relay AlTi operates it opens'the circuit of .relay TSTwhich falls back and AZTi applies the test potential of the secondwaiting line to brush. C of the row preceding line No. i alreadyengaged. If a second call occurs a finder begins to. rotate and stops online No. 2; relay TZT2 operates over the test relay of the finder.Through front contact of TZT2, relay AZTZ operates and applies the testpotential of the third Waiting line to the corresponding terminals inthe nder banks, thus putting the third waiting line in a positionv toreceive a third overload call.

Two cases can be envisaged: (1) When the overload of the operatingpositions is temporary and only one call, for example, is waiting); (2)when the overload is permanent or at least. is of suiiicient durationtov causercomplete operation of the device. y

If we now consider the first case in which a single call is waiting,relay TITI is locked and relay AZTI is operated; as soon as an operatorsposition is free, the chain of contacts controlling the operation of SUTis open, and this relay falls back and closes the following circuit:contact of SUT, back contact DZT3, back contact of D112, back contact ofDZTI, row d of finder C at rest on the first waiting line, relay DTwhich becomes energized and closes the circuit of nder C and of thepilot finger relay PT. Relay TZTI remains locked through its secondwinding by front contact of relay PT which remains operated as long asany finder is hunting, while the line iinder leaves the first waitingline and continues to rotate until it reaches the free operatorsposition. When this position is reached the line finder C stops andrelay PT falls back. Relay TZTI falls back in its turn and relay DZTIoperates in series With AZTI. The operation of DZTI opens the lockingcircuit of AZTI and, since relay AlTl falls back more quickly relaysDZTI and AZTI fall back and the device is now ready for anotheroperation.

If we now take the case when the overload is permanent relays Tlroperate one after the other according to the number of operatorspositions made free. In this case for the rst position available thefirst call leaves the first line, but relays Tl2 and Alr2 beingoperated, relays Alrl andiDlM lock themselves in series through a makecontact of AZ12 and a break contact of D11-2, when relay Pr falls back,i. e. at the end of the search of the rst call.

If a second operators position is made free relay SUT falls back and bythe rest contacts of Dlr3 and DZrZ and the make contact of Dlrl, thesecond call is pushed on. Atfthe end of the search for this call,relaysPr and' Th2. tall back.

and relay DZTZ locks itself thus causing relays` Alrl and Dlrl to fallback. If the overload persists relay TS1' operates through the makecontact of Alr3 and of SUr, thus enabling a new call to be put intowaiting condition.

The present invention has been described in relation to yan embodimentcomprising three `Waiting lines. If there were. more lines the samecycle of operation would occur until the overload is disposed of;

It is seenithatin the embodiment described the calls' are disposed. ofin the order in which they occurred without rotation of the associatedline finders. To enable the circuit to record the order of occurrence ofthe calls even when the load is maximum, it is sufficient to provideenough Waiting lines.

While Ywe haveV described a particular embodiment of our invention forlpurposes of illustration it should `be understood that variousmodications and adaptations thereof may be made within the spirit of theinvention asset forth in the appended claims.

1. A telephonel call distributing `system' cornprising a line finderhaving a plurality rof sets of terminals and cooperating brushes, aplurality of operatorsv positions, a group of said terminals 'beingconnected to said operators positions and a second group of saidterminals being waiting positions, driving means for said line finder,means initiated vby an incoming call for causing the-operation of saiddriving means to cause said line finder to hunt for a free operatorsposition, a contact at eachv operators position adapted to beA closedwhen said operators position is busy, said contacts being connected in achain circuit, a' sourcev of test potential, means for applying a testpotential from said source to one of the terminals of said Waitingpositions, means connected to said chain circuit for operating saidpotential applying means when said contacts are all closed, means forstopping the operation of said driving means when the associated Wiperof said line finder reaches the terminal thus marked with said testpotential, and means under control Vof said last-mentioned operatingmeans for starting the operation of said driving means again when one ofsaid contacts is opened so as to cause said line finder to start huntingagain for a free operators position.

2. A telephonev call distributing system, as dened .in claim 1,. inwhich there are a plurality of line nders with their terminalsmultiplied together, each line nder having its driving means andoperating means therefor, and further comprising means for connecting atest potential to a terminal of a next succeeding waiting position whenone of said line finders is resting on the preceding position, and themeans for starting the operation of a line nder includes means formarking a terminal of the waiting position which has had a line nderresting on it for the longest period of time.

3. A telephone call distributing system, as defined in claim 2, in whichthe means for starting the operation of a line nder after it has restedon one of said waiting positions comprises a relay associated with theline iinder and having its winding connected to the wiper engaging theterminal marked by the last mentioned marking means and having a Contactcontrolling the driving means for said line nder.

PIERRE CHARLES BOREL. JEAN RAYMOND ANTOINE FONT ESCANDE. MARCEL ROGERMAUGE.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,623,336 Dunbar Apr. 5, 19271,711,744 Ostline May 7, 1929 2,176,340 Hensler Oct. 1,'7, 19392,249,362 Irvine July 15, 1941 2,249,486 Molnar July 15, 1941

